I have done all the standard troubleshooting recommendations. I changed out MIDI sport, USB, MIDI cables, and MIDI Keyboard and get the same result..used many different combination of Send SX settings and still have this problem. Any ideas on how to troubleshoot this?

Hi,
sorry for the late reply. In general, your setup should work fine. I have not seen such behavior before!
Maybe you can simplify the setup for testing to see where these extra 00 bytes are inserted?
Does it happen when you connect everything to the Win7 computer? How about the Win10 computer?

One thing we know is that some (USB) MIDI interfaces and some MIDI drivers have problems with System Exclusive messages.

SendSX tries to always receive ALL data, even if malformed. For that, it also displays data which is marked as "corrupt" by Windows. Maybe the inserted 00 bytes are such corrupt bytes. But that still doesn't explain why they occur.